Hydraulic pull-down mechanism for rotary drilling rigs



Aug. 23, 1966 w. M. sTEvENsON 3,258,015

HYDRAULIC PULL-DOWN MECHANISM FOR ROTARY DRILLING RIGS Filed April 15,1964 5 Sheets-Sheet 1 3o LUJ-ao 1 :J FIG. 3. 32 f 2 66 56 28 Flc; 4

J INVJENTOR I FIG. 2. F|G. WILBLR MsTx-:vENsoN ATTORNEYS HYDRAULICPULL-DQWN MECHANISM FOR Filed April 13, 1964 w M. sTEvENsoN 3,268,015

ROTARY DRILLING RIGS 3 Sheets-Sheet 2 sie FIG. 6.

WILBUR M. STEVENSON BY JX,

TORNEYS Aug. 23, 1966 Filed April 13, 1964 W. M. STEVENSON HYDRAULICPULL-DOWN MECHANISM FOR ROTARY DRILLING RIGS 3 Sheets-Sheet 3 j, @so

WILBUR M. STEVENSON.

FIG. 8.

INVENTOR.

ATTORNEYS United States Patent() 3,268,015 HYDRAULIC PULL-DGWN MECHANISMFOR ROTARY DRILLING RIGS Wilbur M. Stevenson, 2675 S. Jasmine, ArapahoeCounty, Colo. Filed Apr. 13, 1964, Ser. No. 359,363 Claims. (Cl.173-147) This invention relates to rotary drilling equipment and morespecifically, to an improved hydraulic pull-down mechanism therefor thatprovides free-spudding while the drill pipe and bit remain attached tothe kelly.

When drilling a well with rotary drilling equipment, a string of drillpipe with a bit fastened to the lower extremity thereof is attached toand suspended from the lower end of a so-called kelly-bar or rod. Thiskelly -bar has exterior grooves or ways adapted to slidably receive keysor the equivalent carried in a drive ibushing turned by the rotatingmechanism of the drilling unit. From time-to-time during the dri-llingoperation it becomes desirable lor necessary to supplement the drillingpressure and this is accomplished by the use of a pull-down mechanismwhich forces the bit into the ground. Devices for this purpose are wellknown in the art, some of them being of the hydraulic type while othersare mechanical.

There is, however, another operation that must be performed fromtime-to-time with a drilling rig that is incompatible with the prior arthydraulic pull-down mechanisms and that is spudding where the drill pipeand bit are raised up and allowed to drop freely back into the hole.There are a number of applications for spudding such as, for example, tofracture down-'hole obstructions, to rapidly displace Well liuids withthe drill pipe acting as a piston so that such fluids are forced towardthevsurface. Regardless of the particular end result to lbe achieved,spudding is a useful operation supplementing the ordinary rotarydrilling action that should be made available `to the driller when it ispossible to do so.

Unfortunately, however, spudding operations are exceedingly diflicultand time-consuming to perform on rotary drilling rigs equipped with theknown hydraulic pull-down mechanisms. The reason is that the pull-downapparatus is connected to the rotary drilling apparatus and prevents thefree-falling action ofthe pipe and bit which are essential to thespudding operation. The only solution, therefore, with the prior artequipment is to completely disconnect the pulldown mechanism from thekelly so that the hoisting winch can raise the drill pipe and release itfor a free drop into the hole. This is no -simple task and is to beavoided whenever possible.

It has now been found in accordance with the teaching of the presentinvention with a novel and improved Vhydraulic pull-down mechanism forrotary drilling rigs can, in fact, be made that will provide for freespudding while remaining connected to the drilling apparatus. Thisdesirable end is accomplished by the simple, but unobvious, expedient ofleaving the head or running block of the pull-down mechanismdisconnected from the hydraulic servo-motor that pushes on same toIimpart additional down-hole pressure on the bit. In other words, withthe piston retracted in its cylinder, the head or running block of thepull-down apparatus runs up and down with the kelly as the latter israised and dropped but said block has little or no effect on thefree-spudding action of the .upper end of the mast that forms the trackin which the Patented August 23, 1966 bit and drill pipe. Conversely, itis only when the piston is extended that the pull-down apparatus becofeseffective to impart a down-hole pressure on the bit. In one embodimentof ythe invention it is necessary to provide a counterweight assembly tocouuterbalance the running block and keep the lines tight when spuddingwhile in the other embodiment, gravity alone accomplishes this end.

It is, therefore, the principal object of the presen-t invention toprovide a novel and improved hydraulic pulldown apparatus for rotarydrilling rigs.

A second objective is the provision o-f a device of the classaforementioned that permits free spudding without being disconnectedfrom the kelly and associated rotating elements.

Another object of the invention herein claimed is to provide a hydraulicpull-down device that necessitates no sacriiice in the supplementarydown-hole pressure it is capable of producing in order to accommodatefree spudding.

Still another objective is to provide a novel disconnected head orrunning block that becomes operatively associated with the drive pistononly during the Work stroke thereof.

An additional objective achieved by the invention herein disclosed andclaimed is the provision of the pull-down equipped with means foraccomplishing free spudding that does not interfere with insertion andremoval of the drill string or other necessary loperations thereon.

Further objects are to provide a rotary drilling apparatus and hydraulicpull-down that is simple, inexpensive, eflicient, versatile, rugged,easy to service, compact and powerful.

Other objects willbe in part apparent and in part pointed outspecifically hereinafter in connection With the description of thedrawings that follows, and in which:

FIGURE -1 is a fragmentary side elevation showing a wheel-mounted rotarydrilling rigr equipped with the preferred embodiment of the hydraulicpull-down mechanism of the present invention, portions of the masthaving `been broken away to reveal the kelly;

FIGURE 2 is a rear elevation of the apparatus shown in FIGURE 1;

FIGURE 3 is Aan enlarged fragmentry view showing the kelly rides withparticular emphasis on the by-pass into which the kelly retracts so asto not obstruct the rod string; i p

FIGURE 4 is an enlarged fragmentary section taken along line 4 4 ofFIGURE 2;

embodiments; and,

FIGURE 8 is an enlarged fragmentary diametrical section showing secondtravelling head and cylinder ar- A rangement usable with either of theprevious embodiments.

Referring now to the drawings for a detailed description of the presentinvention and, initially, to FIGURES 1, 2, 5 and 6 for this purpose, theapparatus is seen to include a wheel-supported frame upon the bed 12 ofwhich is mounted a winch 14, a mast or derrick 16 and a powered rotatingmechanism that has been designated broadly by reference numeral 18. Theaforementioned elements find their mechanical and functionalcounterparts in most of the prior art rotary drilling rigs with theexception of the mast which has been modied to accept the hydraulicpull-down mechanism that comprises the novel feature hereof and whichhas been referred to broadly -by reference numeral 20.

The rotating mechanism 18 includes among other elements a drive bushing22 which receives a kelly rod 24 so as to form a driving connectiontherewith while permitting the latter to slide freely up and downtherein. Such an operative connection is generally accomplished by meansof interlocking splines or the like (not shown) on the mating surfacesof the rod and bushing. A plurality of tubular drill pipe sections (notshown) are suspended from the lower end of the kelly rod and the drillpipe carries a bit on its lower end which bores the hole. Drillingiiuids are circulated through the hollow drill pipe String to removecuttings and perform other operations on the subsurface structures.

The upper extremity of the kelly rod 24 is mounted in a swivel fitting26 that is raised and lowered up and down the mast by means ofthe Winch14 and a cable 28 reeved over one or more pulleys 30 journalled forrotation in the top of the mast. The mast or derrick 24, of course,supports the weight of the drill string and cooperates with the winch toraise and lower the latter so that drill pipe sections can be added andremoved therefrom.

Next with reference to the first six figures of the drawings, it can beseen that the vertical excursions of the drill string and kelly rod areguided by the rear spaced parallel uprights 32 of the mast which arechannel-shaped in the particular form shown to produce tracks withinwhich the trunnions 34 (FIGURE 4) on the outboard ends of the swivelmount 36.ride. In certain instances it becomes necessary to disconnectthe rod string from the kelly and move the latter together with theswivel and its mount on one side in order to clear the top of the mastover the bore and in axial alignment therewith. This is accomplished :bymeans of an olset 38 provided in the upper reaches of the track formedby uprights 32. As best seen in FIGURE 3, the offset comprises nothingmore than an angularly intersecting track section 40 that merges into aninset parallel section 32, the latter ycooperating to deflect the swivelmount 36 forwardly into the dotted line position shown in FIGURES 1 and5.

The above described apparatus is, except for minor differences, commonto both the principal embodiment of the rotary drilling apparatus shownin FIGURES l and 2 as well as the modified embodiment of FIGURES 5 and6. No attempt has been made to illustrate these elements in detail asthey are common to most all rotary drilling rigs of the wheel-mountedvariety and are significant only in that they provide the structuralenvironment upon which the pull-down mechanism acts. In fact, these sameelements may, and do, take many different forms in commerciallyavailable drilling rigs, the ones shown being merely representativethereof.

The pull-down mechanism of the present invention in which the noveltyresides is presented herein as taking two basically different forms, thetirst and preferred one being exemplified in FIGURES 1 and 2 wherein thetravelling head extends upwardly, and the second shown in FIG- URES 5and 6 where the travelling head extends downwardly. Both of theseembodiments are further modilia- 4.- ble to utilize either the hydraulicservo-motor arrangement of FIGURE 7 or of FIGURE 8.

Thus, with specific reference to FIGURES 1 and 2, the principalembodiment of the hydraulic pull-down mechanism 20 of the presentinvention will now be described in detail. A pair of outwardly-openingchannelshaped tracks 44 are mounted on the frame bed 12 so as to extendupwardly therefrom in spaced parallel relation to one another adjacentthe front uprights 46 of the mast to which these tracks or rails arewelded or otherwise connected for support. The travelling head orrunning block 48 of the pull-down apparatus has trunnions 50 journalledthereon which ride in these tracks, the trunnions bein-g most clearlyrevealed in FIGURE 8. The travelling block, therefore, is free to run upand down the mast guided by the aforementioned tracks and in position infront of the kelly, swivel and mounting for the latter. Journalled forrotation within the running -block 48 are a pair of sheaves 52 mountedon opposite ends of a common shaft 54. A pair of fixed-length cables 56are reeved over sheaves 52 with one end dead-ended on the mast asindicated by reference numeral 5S while the opposite end is similarlydead-ended at the swivel mount as shown at 60.

The remainder of the pull-down mechanism comprises a hydraulic cylinderl62 mounted within the mast str-ucture near the upper extremity thereofin inverted position and an extendable piston 64 with la piston rod 66secured thereto adapted to engage che running block or travelling head48 forcing the latter down the mast. A source of hydraulic fluid and apump (not shown) supply duid under pressure to the hydraulic cylinderina manner to either extend or retract the piston rod as will be describedpresent-ly in connection with FIGURES 7 and 8. Thus, it will be apparentthat the introduction 'of lluid under pressure on top of lthe piston 64will extend the travelling `head forcing the kelly down the mast andsupplementing the pressure Ion the bit.

In the other embodiment, namely, that of FIGURES 5 and 6, these sameelements of the pull-down assembly just described in connection withFIGURES 1 and 2 are present, however, they are arranged right-side-uprather than upside-down. For instance, the hydraulic cylinder 62 is nowmounted in the lower end of the mast structure with the piston rod 66emerging from the top. The tracks 44 are 4the same and the travellinghead 48m runs up and down the mast above the cylinder. The travellinghead is slightly modified as shown in that it is considerably smaller soas to clear the swivel assembly when in retracted position at the top ofthe mast. Obviously, the aforementioned dilferences in size of thetravelling head `are functions of the mast dimensions and can, for thisreason, vary .considerably from those illustrated.

Other elements are necessary .in the FIGURES 5 and 6 modificati-on thatwere not needed in the one previously described. For instance, to exerta downward pull on the r-od string, a set of fixed pulleys or sheaves 68must be provided at the base of the mast under which the slightly longercables 56m must -be reeved before bein-g deadended at the swivel. Thus,an upward extension of the piston rod 66 will raise the travelling blockand pulldown, as before, on the drill string.

As will be explained in detail presently, feature of the presentpull-down mechanism that permits freespudding is that the piston rod 66is disconnected from either the piston or the travelling head so thatthe latter remains free to move up and down with the piston fullyretracted within the cylinder. Now, in the principal version of FIGURES1 land 2, the Weight of the travelling 'block 48 will cause it to extendand keep the lines 56 tight even though the piston remains retracted,however, in the present modification, the lines 56m will go slack withthe piston retracted when the kelly rod moves down unless the travellinghead 48m can be raised to take-up this slack. For this reason theFIGURES 5 and 6 modiiication is equipped with -a counterbalance assemblythat has been designated in a general way by reference numeral 70 andwhich includes a cable 72 attached atop the travelling block that isreeved over a fixed sheave 74 in the top of the mast and thence down toa counterweight 76 which counterbalances the weight of the travellingblock 48m, cables 56m and piston rod 66 if the latter is connected tosaid travelling block rather than the piston. Obviously, thiscounterbalance assembly will function to raise the travelling head andtake out all slack in the cables when the kelly and rod string areallowed to drop freely back down the hole as is done when free spud-Finally, with reference to FIGURES 7 and 8, the two different versionsof the hydraulic servo motor assembly have been illustrated, either ofwhich can be used interchangeably on either of the pull-down mechanismsprevi ously described. In both units, the cylinder 62 is essentially thesame having conduits 78 and 80 communic-ating both ends thereof throughwhich fluid may either be introduced or Withdrawn Appropriate valving(not shown) is used to control and reverse the direction of iiuid flowthus making the piston 64 double-acting in accordance with hydraulicprinciples well known to the art. The pistons 64 are, likewise, the samein both versions and constitute nothing novel as many different types ofhydraulic cylinder pistons will function as well and for the samepurpose.

As for the travelling blocks 48a and 48b, both include a box-like frame82 carrying ball-bearing journals 84 that support shaft 54 for rotation.'Ihe sheaves 52 are conventional and xedly attached to the shaft ends.The differences in these travelling blocks 48a and 48h are in theirmanner of makin-g operative connection with the piston rod 66. In theFIGURE 7 version the piston rod 66a is permanently and securely attachedto the travelling block as by welding so that the piston-rod-blockassembly moves as a unit. For this reason the frame 82 is provided withpermanent connecting means 86 adapted for attachment to the piston rod.On the other hand, the FIGURE 8 version has box-like travelling headframe 48b equipped with a recessed socket 88 in the wall thereof facingthe piston rod 66b, the free end of the latter having a concave shape 90adapted to it the aforementioned recess.

The FIGURE 8 version is the simpler of the two and the piston rod 66b isattached to the piston in the usual manner but is disconnected from thetravelling head. Thus, with the piston retracted, the rod 66b isretracted also and only the head 4817 is free to move by itself inresponse to reciprocation of the kelly. Ilhere remains,

-of protection afforded hereby shall be limited only insofar of course,the operative association between the head 48b and rod 66b when thepiston is being extended to exert positive downward pressure on the rodstring.

In the FIGURE 7 version, because the rod 66a is attached to thetravelling head 48a it must be detached from the piston 64 if thedesired free-spudding is to be available. This is accomplished by thesimple expedient of making the piston rod in two telescoping parts, theinner one 92 being connected to the head and freely slidable inside theouter part 94 which is connected to the piston and moves up and down inthe cylinder therewith. Both versions, of course, allow the travellinghead to move independent of the piston when the latter is retracted.

Having thus described the several useful and novel features of thehydraulic pull-down mechanism of the present invention, it will lbe seenthat the many worthwhile objectives for which it was designed have beenachieved. Although but a few specific embodiments of the invention havebeen illustrated and set forth i-n detail, I realize that certain otherchanges and modifications may well occur to those skilled in the artwithin the broad as said limitations are specifically set forth in theappended claims.

What is claimed is:

1. In a rotary drilling device of the type having an upstanding mast,drill pipe supporting means adapted to transmit rotational movement to astring of drill pipe suspended therefrom, drive means connected to thedrill pipe supporting means operative upon actuation to rotate same,swivel means connected to the mast for vertical movement and connectableto the drill pipe supporting means for raising and lowering the drillpipe while it rotates, and winch means connected to the swivel meansoperative upon actuation to raise and lower same, the improved mechanismfor supplementing the downward force exerted on the dri-ll pipe stringwhich comprises: cable means connecting the swivel means to a iixedsupport, a running pulley block in rolling engagement with the cablemeans intermediate the ends thereof operative to exert a downward pullupon the swivel means when a force is applied against said running blockin a direction selected to foreshorten the segment of said cable meansextending between said block and swivel means, and a double-actinghyd-raulic servo-motor including a reciprocatable piston and extendablepiston rod means operatively interconnecting said piston and runningpulley block, said servo-motor upon actuation in a direction to move thepiston from a retracted toward and extended position being operative toextend said piston rod means and force said running block in thedirection required to exert the downward pull upon the swivel means, andsaid servo-motor upon actuation to place the piston in any positionother than fully extended becoming operative to decouple the runningblock and permit limited independent movement thereof so that the swivelmeans can be raised up the mast by the winch means and dropped free ofany damping action that would otherwise be exerted thereon by thepiston.

2. The improved hydraulic pull-down mechanism as set forth in claim 1 inwhich the piston rod means is iixedly attached to the piston forreciprocal movement therewith and the running block is detached from thepiston rod means.

3. The hydraulic pull-down mechanism as set forth in claim 1 in whichthe piston rod means comprises two telescoping elements, one of which isattached to the piston and the other attached to the running block.

4. The hydraulic pull-down mechanism as set forth in claim 1 in which:the hydraulic servo-motor is fastened to the mast in an upright butinverted position such that the piston rod means emerges from the bottomthereof, and the running block is positioned underneath the servomotorwith the cable means reeved from the 4fixed support and around theunderside of the pulleys before passing upwardly to the swivel means.

5. The hydraulic pull-down mechanism as set forth in claim 4 in whichthe piston rod means is tixedly attached to the piston for reciprocalmovement therewith and the running lblock is detached from the pistonrod means.

6. The hydraulic pull-down mechanism as set forth in claim 4 in whichthe piston rod means comprises two telescoping elements, one of which isattached to the piston and the other attached to the running block.

7. The hydraulic pull-down mechanism as set forth in claim 1 in which:the hydraulic servo-motor is fastened to the mast in an upright positionsuch that the piston rod means emerges from the top thereof, the runningblock is located above the servo-motor, means comprising a fixed pulleyblock is located at the base of the mast, and the cable means is reevedfrom a fixed support over the pulleys of the running block thence downand underneath the pulleys of the fixed-block before passing upwardly tothe point of attachment to the swivel means.

8. The hydraulic pull-down mechanism as set forth in claim 5 in whichthe piston rod means is fixedly attached to the piston for reciprocalmovement therewith land the running block is detached from the pistonrod means.

9. The hydraulic pulldown mechanism as set forth in claim 5 in which thepiston rod means comprises two telesc-oping elements, one of which isattached to the piston and the other attached to the running block.

10. The hydraulic pull-down mechanism as set forth in claim 5 in which:a second lfixed pulley block is located in the top of the nest, secondcable means is attached -to the Vrunning block and reeved over thesecond xed pulley block, and a 'counterweight attached to the free endof the second cable means adapted to counterxbalance the weight of therunning block and first cable means so as 3 tracted and the swivel meansis elevated in position for free-fall.

References Cited by the Examiner UNITED S'lATES` PATENTS 2,179,31611/1939 Anderson 173-147 2,215,928 9/1940 Hornbrook 173-151 2,956,78210/l960 `Mistrot 173-147 3,172,485 3/1965 Spannhake 173-147 3,190,3786/1965 Davey et al 173-147 MILTON KAUFMAN, 'Primary Examiner.

to eliminate slack in the latter when the piston is rel5 L. P. KESSLER,Assistant Examiner.

1. IN A ROTARY DRILLING DEVICE OF THE TYPE HAVING AN UPSTANDING MAST,DRILL PIPE SUPPORTING MEANS ADAPTED TO TRANSMIT ROTATIONAL MOVEMENT TO ASTRING OF DRILL PIPE SUSPENDED THEREFROM, DRIVE MEANS CONNECTED TO THEDRILL PIPE SUPPORTING MEANS OPERATIVE UPON ACTUATION TO ROTATE SAME,SWIVEL MEANS CONNECTED TO THE MAST FOR VERTICAL MOVEMENT AND CONNECTABLETO THE DRILL PIPE SUPPORTING MEANS FOR RAISING AND LOWERING THE DRILLPIPE WHILE IT ROTATES, AND WINCH MEANS CONNECTED TO THE SWIVEL MEANSOPERATIVE UPON ACTUATION TO RAISE AND LOWER SAME, THE IMPROVED MECHANISMFOR SUPPLEMENTING THE DOWNWARD FORCE EXERTED ON THE DRILL PIPE STRINGWHICH COMPRISES: CABLE MEANS CONNECTING THE SWIVEL MEANS TO AFFIXEDSUPPORT, A RUNNING PULLEY BLOCK IN ROLLING ENGAGEMENT WITH THE CABLEMEANS INTERMEDIATE THE ENDS THEREOF OPERATIVE TO EXERT A DOWNWARD PULLUPON THE SWIVEL MEANS WHEN A FORCE IS APPLIED AGAINST SAID RUNNING BLOCKIN A DIRECTION SELECTED TO FORESHORTEN THE SEGMENT OF SAID CABLE MEANSEXTENDING BETWEEN SAID BLOCK AND SWIVEL MEANS, AND A DOUBLE-ACTINGHYDRAULIC SERVO-MOTOR INCLUDING A RECIPROCATABLE PISTON AND EXENDABLEPISTON ROD MEANS OPERATIVELY INTERCONNECTING SAID PISTON AND RUNNINGPULLEY BLOCK AND SERVO-MOTOR UPON ACTUATION IN A DIRECTION TO MOVE THEPISTON FROM A RETRACTED TOWARD AND EXTENDED POSITION BEING OPERATIVE TOEXTEND SAID PISTON ROD MEANS AND FORCE SAID RUNNING BLOCK IN THEDIRECTION REQUIRED TO EXERT THE DOWNWARD PULL UPON THE SWIVEL MEANS, AND